爲什麼我會得到「輸入參數值」？

Question

我試圖列出所有發佈者在數據庫上的一本書。

查詢：

SELECT Publisher 
FROM book 
GROUP BY Publisher 
HAVING COUNT(book) = 1; 

Answer 1

我的猜測是該問題是在這裏...

HAVING COUNT(book) = 1 

表被命名爲book。除非該表格還包含名爲book的字段，否則訪問將被混淆。

如果你想看到Publisher對只有一個排，使用此...

SELECT Publisher 
FROM book 
GROUP BY Publisher 
HAVING COUNT(*) = 1;